The objective of this proposal is to obtain continuing support for the Harvard Medical School Research Center in Diagnostic Radiology in which radiologic tools in conjunction with other physiologic, pharmacologic, morphologic, biochemical, and biophysical methods are creatively applied to the solution of biomedical problems. The Center supports a nucleus of investigators in a broad, continuing program oriented particularly toward elucidating the characteristics of the regional circulations in mammals but by no means limited to such a focus. It also provides a well-equipped research facility sufficiently versatile and flexible to respond quickly to new and promising directions in research undertaken by faculty and trainees alike. Because there are many combined basic laboratory and clinical research projects already underway, a particular objective of the center is the rapid transfer of advances made in the laboratory to the clinic. Furthermore, the multidisciplinary and multifaceted approaches to problems provide an objective measure for the interpretation of data obtained with radiographic methods. In the process of developing its research potential, the Center also serves as a training resource for investigators and academic radiologists drawn particularly from the Harvard departments and from the medical schools of the New England region.